The present invention relates to an image data processing method, an image data processing apparatus and a digital still camera. More particularly, the invention relates to an image data processing method or the like capable of obtaining a preferable reproduction image by storing image data of a screen into memory means, reading the image data from the memory means in a unit of block consisting of a predetermined number of pixels, performing compression coding process on the image data in the unit of block and, when the image data is short of the unit of block in being read in the unit of block, compensating a short amount thereof by using data on an end side of the image.
Conventionally, in recording image data on a recording medium, a format of the image data recorded on the recording medium is converted into a format of data that a reproducing apparatus can reproduce, and the resultant data is recorded.
For example, in case of recording image data obtained by photographing an object with a digital still camera on a memory card attached to the digital still camera, the image data is recorded on the memory card in a format such as JPEG (Joint Photographic Experts Group), FlashPix (format jointly developed by the four companies of Kodak, Hewlett-Packard, LivePicture, and Microsoft) in accordance with a data reproducing apparatus.
In the formats of JPEG, FlashPix and the like, image data is processed in a unit of block consisting of a predetermined number of pixels. For example, in the JPEG format, image data is processed in a unit of block of “8 pixels×8 pixels”. In the FlashPix format, image data is processed in a unit of a block of “64 pixels×64 pixels”. When a format of the image data obtained by a digital still camera is converted into the format of data such as JPEG and FlashPix, it is necessary to eliminate image data of excessive pixels or add image data to a short amount of pixels.
When image data of excessive pixels is eliminated, the size of a recorded image becomes smaller than that of the photographed image. When image data of a short amount of pixels is added, image data that has no relation with the photographed image is added. When the recorded image data is reproduced, the photographed image and also the image based on the added image data are displayed.
In case of performing a compression coding process on recording the image data to reduce the amount of data, if image data that is not related to the photographed image is added, not only the data compression ratio decreases but the picture quality of an image obtained by decompressing the compressed data deteriorates.
It is therefore an object of the invention to provide an image data processing method, an image data processing apparatus and a digital still camera, which can obtain a preferable image based on processed image data even if the image data is short of the unit of block when the image data is processed in the unit of block.